Urinary incontinence, or an inability to control urinary function, is a common problem afflicting people of all ages, genders, and races. Various muscles, nerves, organs and conduits within the urinary tract cooperate to collect, store and release urine. A variety of disorders may compromise urinary tract performance, and contribute to incontinence. Many of the disorders may be associated with aging, injury or illness.
In some cases, urinary incontinence can be attributed to improper sphincter function, either in the internal urinary sphincter or external urinary sphincter. For example, aging can often result in weakened sphincter muscles, which causes incontinence. Some patients may also suffer from nerve disorders that prevent proper triggering and operation of the bladder or sphincter muscles. Nerves running though the pelvic floor stimulate contractility in the sphincter. A breakdown in communication between the nervous system and the urinary sphincter can result in urinary incontinence. As used herein, the term “urinary incontinence” include disorders in which urination occurs when not desired, such as stress or urge incontinence, and disorders in which urination does not occur as desired, such as urinary retention disorder.
Therapies for treating urinary incontinence include delivery of electrical stimulation and delivery of therapeutic substances. For example, delivery of electrical stimulation from an implantable medical device to nerves in the pelvic floor, such as the sacral and pudendal nerves, may provide an effective therapy for urinary incontinence. Electrical stimulation of the sacral nerve may induce sphincter constriction and thereby close or maintain closure of the urethra at the bladder neck. In addition, electrical stimulation of the bladder wall may enhance pelvic floor muscle tone and assist fluid retention in the bladder or voiding fluid from the bladder.